Explosively actuated tool



March 9, 1965 E. HOLZ 3,172,117

EXPLOSIVELY ACTUATED TOOL Filed Aug. 2, 1962 2 Sheets-Sheet l- 4 2 Ba 151/ 12 a I M j viv v x 9 M F/ge Inventor Eff: A H (L March 9, 1965 HOLZ 3,172,117

EXPLOSIVELY ACTUATED TOOL Filed Aug. 2, 1962 2 Sheets-Sheet 2 United States Patent 3,172,117 EXPLOSIVELY ACTUATED TOOL Erich Holz, 67-69 Bankstrasse, Dusseldorf, Germany Filed Aug. 2, 1962, Ser. No. 214,403 Claims priority, application Germany, Aug. 3, 1961,

E 21,485; Mar. 9, 1962, E 22,519

Claims. (Cl. 1-44.5)

The present invention relates to devices for introducing bolts, nails, studs and similar fasteners into masonry walls of building structures or the like, and more particularly to an explosively actuated fastener driving tool of the type in which a bolt or another fastener is propelled by an explosive-containing cartridge. the invention relates to improvements in the construction of the barrel, of the barrel holder and of the cartridgereceiving element in such tools.

Conventional explosively actuated fastener driving tools of which I am aware at this time are rather expensive because they are invariably provided with complicated ejecting devices which facilitate extraction of a spent cartridge from the barrel. Furthermore, many known explosively actuated tools cannot be fired in rapid succession because the cartridge and/or the cartridgereceiving element is likely to stick in the barrel after the fastener is fired into a wall or the like so that even an ejecting device cannot always insure that the cartridge will be readily removed from the chamber to provide cartridges and cartridge-receiving elements the cartridgereceiving element is accommodated in its chamber with at least some play which is highly undesirable'for obvious reasons.

Accordingly, it is an important object of my invention to provide a very simple and inexpensive explosively actuated fastener driving tool which is constructed and assembled in such a way that a spent cartridge may be rapidly and conveniently removed from the barrel without it being necessary to equip the tool with any ejecting or stripping means.

Another object of the invention is to provide a tool of the just outlined characteristics wherein a spent cartridge and its receptacle are automatically separated from the barrel as soon as the barrel is detached from its holder preparatory to insertion of a new cartridge.

A further object of my invention is to provide an improved cartridge-receiving element for use in a tool of the above outlined characteristics.

An additional object of the invention is to provide a fastener driving tool which is constructed and assembled in such a way that the danger of accidentally firing a loaded cartridge during connection of the barrel to its holder is eliminated in a very simple manner.

A concomitant object of the invention is to provide a fastener driving tool wherein the cartridge and the cartridge-receiving element are automatically in positions ready for firing when the barrel is properly connected with its holder.

With the above objects in view, the invention resides in the provision of an explosively actuated fastener driving tool of the type wherein the fastener is positioned ahead of an explosive-containing cartridge and which comprises a barrel holder having a substantially fiat surface, a barrel formed with a through bore and having an end portion which is respectively more distant from or nearer to the surface of the holder when the barrel is moved from an inoperative to a ready-to-fire position,

. a chamber provided in the end portion of the barrel and having an open end which is adjacent to the surface of the holder when the barrel is moved to its ready-to-fire posi- Still more particularly,

, 3,172,117 Patented Mar. 9, 1965 ready-to-fire position whereby the sleeve fills the chamber at the time the tool is ready to explode thecharge in the cartridge and to drive the fastener into a wall or.

the like. The sleeve expands and is thereby separated from the wall bounding the chamber in a fully automatic.

way as soon as the barrel is moved to its inoperative position. i

The novel features which are considered as characteristic of the invention are setforth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additonal objects and advantages thereof, will be best understood from the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a fragmentary axial section through an explosively actuated tool which embodies one form of my invention and whose barrel is shown in ready-to-fire position; I

FIG. 2 is a similar section through the tool with the barrel shown in inoperative position;

FIG. 3 is a fragmentary axial section through a slightly modified tool wherein the barrel holder and the elastic sleeve are provided with cooperating retaining means preventing rotation of the sleeve when the barrel is caused to rotate with respect to the holder; and

FIG. 4 is an enlarged perspective view of an elastic sleeve which is utilized in the tool of FIG. 3.

Referring now in greater detail to the drawings, and first to FIGS. 1 and 2, there is shown an explosively actuated fastener driving tool which comprises an elongated barrel 1 having a rear end portion 2 received in a recess provided in a barrel holder 3 which is anchored in a housing or stock 4. The end portion 2 and the barrel holder 3 are provided with cooperating coupling means 5 which lock the barrel in the ready-to-fire position of FIG. 1. In the illustrated embodiment, the coupling means 5 assumes the form of internal threads in the recess of the holder 3 and mating external threads on the end portion 2. If desired, such coupling means may assume the form of a bayonet lock or the like. When the barrel 1 has been moved to the ready-to-fire position of FIG. 1, the end face of its end portion 2 abuts against a substantially fiat surface 10 of the holder 3, this surface constituting the bottom wall of the recess in which the end portion 2 is received when the threads of the coupling means 5 are caused to mesh with each other.

The end portion 2 is formed with a specially config urated coaxial chamber 6 bounded by a frustoconical Wall 7 which diverges toward the surface 10, and by an internal annular shoulder 8 which is disposed in a plane perpendicular to the axis of the barrel 1. It will be noted that the chamber 6 has an open end which is adjacent to the surface 10. The chamber 6 is coaxial to and communicates with the through bore 9 of the barrel 1.

The holder 3 is provided with a cylindrical guide 11 for a firing pin 12, and the front end face of the guide 11 is flush with the surface 10. The trigger mechanism which causes the pin 12 to strike against a cartridge A and to thus detonate the explosive charge of the cartridge is of conventional design and isnot shown in the drawings.

The cartridge A is received in a specially configurated elastically compressible sleeve 13 which consists of acetate plastic or another material having the characteristics of rubber. This sleeve has a frustoconical mantle 13a whose transverse dimensions are slightly less than the transverse dimensions of the wall 7 when the sleeve is not subjected to compression so that the latter may be readily inserted into the chamber 6 when the barrel is detached from its holder. However, the axial length of the sleeve 13 is somewhat greater than the axial length of the chamber 6 whereby the sleeve projects rearwardly and beyond the end face of the end portion 2 when the barrel assumes the inoperative position of FIG. 2 in which the end portion 2 is spaced from the surface 10. In other words, when the barrel is moved from the position of FIG. 2 to the position of FIG. 1, the axial length of the sleeve 13 is reduced with attendant expansion of the sleeve in the radial direction thereof whereby the mantle 13a abuts against the wall 7 and the sleeve fills the entire chamber 6.

For example, when the sleeve 13 is not subjected to axial compression, its axial length a exceeds by a distance b the axial length of the chamber 6. The distance b may be about 0.3 mm, if the axial length of the chamber 6 is about 13.9 mm., i.e., if the axial length of the uncompressed sleeve is 14.2 mm. The width c of the conical gap 15 between the mantle 13a and wall 7 in uncompressed state of the sleeve 13 is then about 0.05 mm. Such dimensioning of the sleeve 13 and of the chamber 6 insures that the chamber is completely filled by the sleeve when the barrel 1 is rotated in a sense to move its end portion 2 axially from the position of FIG. 2 to the position of FIG. 1 in which the end face of the end portion 2 is very close to or abuts against the surface 10.

The sleeve 13 and the cartridge A are'normally furnished as a factory-assembled unit so that all an operator has to do is to unscrew the end portion 2 from the holder 3, to insert a preassembled unit into the chamber 6 in such a Way that the front end face of the sleeve 13 abuts against the shoulder 8, and to reestablish the connection between the end portion 2 and the holder 3 by driving the end portion home to such an extent that the surface 10 causes axial compression and resultant radial expansion of the sleeve. The sleeve 13 cannot collapse during application of compressive stresses thereto because its bore receives the casing of the cartridge A.

In accordance with a feature of my invention, the

angle p which the wall 7 and the mantle 1311 make with the axis of the bore 9 and hence with the axis of the chamber 6 is at least 15 to make sure that the sleeve 13 is automatically separated from the end portion 2 when the barrel 1 is moved to or leftwardly beyond the inoperative position of FIG. 2. In other words, if the angle p is at least 15 or more, a compressed plastic sleeve 13 will contract radially and will cause its mantle 13a to slide with respect to the metallic wall 7 as soon as the end portion 2 begins to move away from the metallic surface 10 because friction between the plastic mantle 13a and the metallic wall 7 is insutficient to counteract energy which the sleeve 13 stores when it is compressed into the chamber 6.

When the charge contained in the cartridge A is exploded by the pin 12 to propel a fastener through the bore 9 and into a piece of masonry or the like, the sleeve 13 sustains no additional deformation because its com pression between the walls bounding the chamber 6, between the surface 10, and between the casing of the cartridge A is three-dimensional. Consequently, the likelihood that the sleeve would be damaged or destroyed during firing or that the cartridge would move out of alignment with the bore 9 is practically non-existent.

It will be noted that the tool of my invention need not be provided with an ejecting or extracting device because the configuration of the chamber .6 and the configuration and dimensioning of the cartridge-receiving sleeve 13 are selected in such a way that the separation (radial contraction and axial expansion) of the sleeve from the walls of the chamber is fully automatic as soon as the barrel 1 is moved from its ready-to-fire to its inoperative position. Such automatic separation of the sleeve from the end portion 2 of the barrel takes place even if the material of the sleeve is heated during firing of the explosive charge and would normally tend to adhere to the barrel. Of course, the angle p may be varied in dependency on the composition of the material of the barrel and/or the sleeve as well as on elastic characteristics of the sleeve. It is important that the tangent of the angle p is greater than the coefficient of friction [A between the compressed mantle 13a and the wall 7, i.e that it exceeds the self-locking limit at which the compressed sleeve cannot overcome friction or adhesive forces acting between the mantle 13a and wall 7.

FIG. 3 illustrates a slightly medified explosively actuated tool which is very similar to the tool of FIGS. 1 and 2 excepting that it utilizes a different cartridge-receiving sleeve 113 and a different barrel holder 103. The coaxial bore of the sleeve 113 accommodates a cartridge A in such a way that the cartridge is coaxially received in the chamber 6 when the sleeve is inserted into the end portion 2 of the barrel 1. FIG. 3 shows the barrel 1 in ready-to-fire position in which the rear surface 14 of the sleeve 113 is in abutment with the surface 10 of the holder 163 so that the sleeve is compressed axially and expands radially into face-to-face abutment with the wall 7 of the chamber 6. The rear surface 14 of the sleeve 113 is somewhat larger than the corresponding surface of the sleeve 13 and is provided with a concentric annular groove 16 (see particularly FIG. 4) whose undulate or toothed bottom wall consists of alternating crests and troughs. The groove '16 is surrounded by a smooth annular surface portion 19 which extends to the mantle 113a. A second smooth annular surface portion 18 is surrounded by the groove 16 and extends inwardly toward the cartridge-accommodating bore 25 of the sleeve 113. The crests of the bottom wall in the groove 16 Cooperate with a pin-shaped projection 17 which is mounted in the barrel holder 103 and which extends beyond the surface 10 so that the groove 16 and the projection 17 together constitute a retaining means which prevents rotation of the sleeve 113 when the barrel 1 is rotated with respect to the holder in order to move its end portion 2 into or away from abutment with the surface 10. It will be noted that the width of the groove 16, as measured in the radial direction of the surface 14, approximates or equals the width of each of the annular surface portions 18, 19. The projection 17 is eccentric to the axis of the barrel 1 and penetrates into one of the troughs in the bottom wall of the groove 16 when the teeth of the coupling means 5 are caused to mesh and the barrel 1 is rotated to move its end portion 2 axially toward the surface 10.

In the position of FIG. 3, the end portion 2 of the barrel 1 cooperates with the surface 10 of the holder 103 to compress the sleeve 113 axially and to cause radial expansion of this sleeve so that the latter fills the chamber 6. The depth of the groove 16 is rather negligible in order to make sure that the volume of that portion of the chamber 6 which is not filled with the material of the sleeve 113 when the barrel 1 is in the ready-tofire position of FIG. 3 is reduced to a negligible minimum. In fact, the sole empty space not filled by the sleeve 113 is the combined space of the troughs in the groove 16 and, since this groove is bounded by smooth annular surface portions 18, 19 which abut against the surface 10, the sleeve 113 cannot sustain any appreciable additional deformation when the charge contained in the cartridge A is exploded to propel the fastener into a work surface.

An important advantage of the retaining means 16, 17 is that the sleeve 113 cannot rotate with the end portion 2 when the barrel 1 is rotated in a sense to move the end portion 2 away from the surface 10 of the holder 103. Consequently, even if the material of the sleeve would tend to adhere to the walls bounding the chamber 6, the sleeve is separated from the barrel in a fully automatic way because the pin 17 and a selected crest in the bottom wall of the groove 16 cooperate to prevent rotation of the sleeve. The rotating end portion 2 is then automatically separated from the mantle 113a. and the sleeve can drop from the chamber 6 by gravity as soon as the end portion is removed from the recess inthe holder 103. The likelihood that the material of the sleeve 113 would adhere to the end portion 2 is especially pronounced at the tip 2th of the sleeve (see FIG. 4) which is adjacent to the shoulder 8 and which is heated to a high temperature when the tool is fired.

The force necessary to unscrew the end portion 2 from the holder 103 is increased only negligibly when the tool of my invention is constructed in a manner as shown in FIG. 3, i.e., when the tool comprises a retaining means which prevents rotation of the sleeve 113 with the barrel 1 at least shortly before the barrel is moved to its readyto-fire position'as well as when the barrel begins to move from such ready-to-fire position to its inoperative position. Even if the tip 20 of the sleeve 113 tends to adhere to the walls of the chamber 6, the force necessary for moving the barrel to its inoperative position is not very large so that it requires no substantial effort to remove the barrel and to simultaneously separate the sleeve from the end portion 2. Another advantage of the retaining means 16, 17 is that it prevents accidental firing of the tool at the time the barrel 1 is moved to its ready-to-fire position. Thus, if the sleeve 113 were free to rotate with the end portion 2 at the time the firing pin 12 projects beyond the surface 10 of the barrel holder 103, the tip of the pin 12 would rub against the cartridge A and could cause explosion of the charge contained in this cartridge. Such rubbing action between the pin 12 and the cartridge A is not possible when the projection 17 enters a trough in the groove 16 because the sleeve 113 is then automatically held against rotation with the barrel. Rotation of the sleeve 113 prior to engagement between the projection 17 and the bottom wall of the groove 16 cannot cause firing of the tool because the material of the sleeve is subjected to axial compression only at the time the rear surface of the sleeve comes into actual abutment with the surface 10. The projection 17 may be replaced by a tooth which then cooperates with a toothed surface portion of the sleeve in the same manner as described in connection with lFIG. 3.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an explosively actuated fastener driving tool of the type from which the fastener is expelled in response to detonation of explosive contained in a cartridge, in combination, a barrel holder having a substantially flat surface; an elongated barrel having a through bore, said barrel comprising an end portion having an annular rear end face and an annular internal shoulder spaced forwardly from said rear end face and said barrel being movable with respect to said holder between an inoperative and a ready-to-fire position in which said rear end face thereof is respectively spaced from and abuts against said surface, said end portion having a frustoconical internal chamber which extends between said shoulder and said end face and is coaxial with said bore and which diverges toward and has an open end adjacent to said surface when the barrel is in said ready-to-fire position; and a frustoconical cartridge-receiving sleeve of elastically compressible material in said chamber, the axial length of said sleeve in uncompressed condition thereof exceeding the axial length of said chamber whereby said sleeve abuts against said surface and against said shoulder and is sub- 6 jected to axial compression therebetween and expands radially to fill said chamber when the barrel is in'said ready-to-fire position.

2. In an explosively actuated fastener driving tool of the type from which the fastener is expelled in response to detonation of explosive contained in a cartridge, in

combination, a barrel holder having a substantially flat surface; an elongated barrel having a ,throughbore, said barrel comprising an end portion having an annular rear end face and an annular internal shoulder spaced forwardly from said rear end face and said barrel, being movable with respect to said holder between an inoperative and a read-to-fire position in which said rear end face thereof is respectively spaced from and abuts against said surface, said end portion having a frustoconical internal chamber which is coaxial with said bore and which extends between said shoulder and said end face and diverges toward and has an open end adjacent to said surface when the barrel is in said ready-to-fire position; and a frustoconical cartridge-receiving sleeve of elastically compressible material in said chamber, the axial length of said sleeve in uncompressed condition thereof exceeding the axial length of said chamber whereby said sleeve abuts against said surface and against said shoulder and is subjected to axial compression therebetween and expands'radially to fill said chamber when the barrel is in said read-to-fire position, said end portion having a conical wall bounding said chamber and the inclination between said wall and the axis of said chamber being at least 15 whereby the sleeve is free to expand automatically in the axial direction of and beyond the open end of said chamber when the barrel is moved to said inoperative position.

3. A combination as set forth in claim 2, wherein said sleeve has a conical mantle whose inclination with respect to the axis of said sleeve is the same as the inclination of said wall and wherein the transverse dimensions of said wall exceed slightly the transverse dimensions of said mantle when the sleeve is in uncompressed condition.

4. In an explosively actuated fastener driving tool of the type from which a fastener is expelled in. response to detonation of explosive contained in a cartridge, in combination, a barrel holder having a substantially flat surface; a barrel having a through bore, said barrel comprising an end portion having an annular rear end face and an annular internal shoulder spaced forwardly from said rear end face and said barrel being rotatable with respect to said holder to move in the axial direction thereof between an inoperative and a ready-to-fire position in which said rear end face thereof is respectively more distant from and nearer to said surface, said end portion having a chamber extending between said shoulder and said end face, said chamber communicating with said bore and having an open end adjacent to said surface when the barrel is in said ready-to-fire position; a cartridgereceiving sleeve of elastically compressible material in said chamber, said sleeve abutting against said surface and against said shoulder and being subjected to compression therebetween to fill said chamber when the barrel is in said ready-to-fire position; and cooperating retaining means provided on said sleeve and on said holder for preventing rotation of said sleeve with respect to said holder when said barrel is rotated to move toward or away from said ready-to-fire position.

5. A combination as set forth in claim 4, wherein said sleeve has a surface abutting against the surface of said holder in ready-to-fire position of said barrel, said retaining means comprising at least one projection extending beyond one of said surfaces and at least one groove provided in the other surface and adapted to receive said projection.

6. A combination as set forth in claim 4, wherein said sleeve has a substantially fiat surface abutting against the surface of said holder in the ready-to-fire position of said barrel, said retaining means comprising an annular groove provided in the surface of said sleeve and having a bottom wall consisting of alternating crests and troughs, and a pin projecting beyond the surface of said holder and extending into said groove to engage one of said crests and to thereby prevent rotation of said sleeve with said barrel.

7. A combination as set forth in claim 6, wherein the surface of said sleeve comprises a smooth outer annular portion surrounding said groove and a smooth inner annular portion surrounded by said sleeve, said annular portions abutting against the surface of said holder when the barrel assumes said ready-to-fire position.

8. A combination as set forth in claim 7, wherein the width of the annular groove, as measured in the radial direction of the surface on said sleeve, approximates the width of each of said annular portions.

9. In an explosively actuated fastener driving tool of the type from which the fastener is expelled in response to detonation of explosive contained in a cartridge, in combination, a barrel holder having a substantially fiat surface; an elongated barrel having a through bore; said barrel comprising an end portion and being movable with respect to said holder between an inoperative and a readyto-fire position in which said end portion is respectively spaced from and abuts against said surface, said end portion having an internal chamber which is coaxial with said bore and which diverges toward and has an open end axial compression and expands radially to fill said cham her when the barrel is in said ready-to-fire position, said sleeve having a frustoconical mantle and a tip which abuts against said shoulder in ready-to-fire position of said barrel, said'sleeve being compressed between said shouldcr and said surface, said mantle and said wall making an angle of at least 15 with the axis of said sleeve.

10. A tool as set forth in claim 9, wherein said sleeve consists of synthetic plastic material.

References Cited by the Examiner UNITED STATES PATENTS 2,984,836 5/61 Schenkel 1-445 3,049,714 8/62 Bumiller 1--44.5

FOREIGN PATENTS 776,372 6/57 Great Britain.

GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. IN AN EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL OF THE TYPE FROM WHICH THE FASTENER IS EXPELLED IN RESPONSE TO DETONATION OF EXPLOSIVE CONTAINED IN A CARTRIDGE, IN COMBINATION, A BARREL HOLDER HAVING A SUBSTANTIALLY FLAT SURFACE; AN ELONGATED BARREL HAVING A THROUGH BORE, SAID BARREL COMPRISING AN END PORTION HAVING AN ANNULAR REAR END FACE AND AN ANNULAR INTERNAL SHOULDER SPACED FORWARDLY FROM SAID REAR END FACE AND SAID BARREL BEING MOVABLE WITH RESPECT TO SAID HOLDER BETWEEN AN INOPERATIVE AND A READY-TO-FIRE POSITION WHICH SAID REAR END FACE THEREOF IS RESPECTIVELY SPACED FROM AND ABUTS AGAINST SAID SURFACE, SAID END PORTION HAVING A FRUSTOCONICAL INTERNAL CHAMBER WHICH EXTENDS BETWEEN SAID SHOULDER AND SAID END FACE AND IS COAXIAL WITH SAID BORE AND WHICH DIVERGES TOWARD AND HAS AN OPEN END ADJACENT TO SAID SURFACE WHEN THE BARREL IS IN SAID READY-TO-FIRE POSITION; AD A FRUSTOCONICAL CARTRIDGE-RECEIVING SLEEVE OF ELASTICALLY COMPRESSIBLE MATERIAL IN SAID CHAMBER, THE AXIAL LENGTH OF SAID SLELEVE IN UNCOMPRESSED CONDITION THEREOF EXCEEDING THE AXIAL LENGTH OF SAID CHAMBER WHEREBY SAID SLEEVE ABUTS AGAINST SAID SURFACE AND AGAINST SAID SHOULDER AND IS SUBJECTED TO AXIAL COMPRESSION THEREBETWEEN AND EXPANDS RADIALLY TO FILL SAID CHAMBER WHEN THE BARREL IS IN SAID READY-TO-FIRE POSITION. 